This invention relates to a two step process for the selective production of 1,4- and 1,2-butanediol. More particularly, this invention is directed toward a process which comprises reacting 1,3-butadiene with tert-butyl hydroperoxide in the presence of a supported cobalt catalyst, followed by catalytic hydrogenation of the di(tert-butylperoxy) butenes obtained thereby.
Butadiene is widely available as a co-product of steam-cracking olefins plants or from the dehydrogenation of butylenes from refineries. Methods of converting butadiene to other commercially valuable compounds, such as butanediols, are thus of interest. The more valuable butanediol is 1,4-butanediol, which finds applications as a solvent, an intermediate for the production of tetrahydrofuran and a component for a variety of polyurethanes, plastics and resins. Classical Reppe chemistry is currently used for the commercial production of 1,4-butanediol from acetylene and formaldehyde. Due to the cost and explosive tendency of acetylene, an alternative route to 1,4-butanediol is desirable. With the instant invention, a simple and effective alternative process for the production of butanediols from a butadiene feedstock has been devised. The process affords both high yields and selectivities to butanediols, while favoring the production of the more valuable 1,4-butanediol.
Various paths leading to 1,4-butanediol from 1,3-butadiene have been demonstrated; they include acetoxylation (British Pat. No. 1,170,222), oxidation (U.S. Pat. No. 3,238,225), hydroboration (U.S. Pat. No. 3,060,244) and hydrogenation of a butadiene-oxygen copolymer (German Pat. No. 2,232,699 and U.S. Pat. No. 2,879,306). In contrast, the instant process reacts tert-butyl hydroperoxide (TBHP) with 1,3-butadiene to form a mixture of di(tert-butylperoxy)butenes, which are subsequently hydrogenated to butanediols.
Kharasch et al, J. Org. Chem., 18, 322 (1953), disclose a similar process for the production of di(tert-butylperoxy)butenes using a homogeneous cobalt napthenate catalyst, but without the use of a solvent. The use of such a liquid catalyst renders separation of the products from the catalyst difficult and results in a very long reaction time; these problems are avoided by the present heterogeneous cobalt catalyst. Kharasch et al also disclose a subsequent hydrogenation step using a palladium on charcoal catalyst, although the yields or selectivities obtained are not made clear.
Kharasch and Fono, J. Org. Chem., 24, 72 (1959), disclose the reaction of hydroperoxides with olefins using cobaltous salts as catalysts. In the additional presence of a one-electron oxidizing agent, an alkylperoxy olefin (containing only one peroxy grouping) is formed.
Milas et al, J. Am. Chem. Soc., 68, 205 (1946), disclose the hydrogenation of di-tert-butylperoxide over a Raney nickel catalyst to yield tert-butyl alcohol.
In Kochi, J. Am. Chem. Soc., 84, 2785 (1962), TBHP and butadiene react in the presence of copper and/or iron-containing catalysts to form tert-butoxybutenylacetates or butoxymethoxybutenes, neither of which contain peroxy groupings.